This invention relates generally to rigid thin-walled annular shells and specifically to such structural shells built up layerwise from glassy alloy strips and selected bonding means.
Thin-walled shells are hollow structures having a wall thickness much smaller than the wall radius of curvature and are typically characterized by a radius to thickness ratio of at least about 10. Such structures are highly efficient in sustaining nonbending loads, i.e. loads that produce planar (biaxial) stress within the wall but no significant radial (triaxial) stress. These shells have high strength and rigidity relative to their weight (high specific strength) and are especially suited for such applications as light weight torsional shafts and conduits or vessels to contain high pressure fluids.
Thin-walled shells, such as tubing, may be constructed as a composite material by building up the wall layerwise from high strength strips, or other filaments, in combination with a bonding matrix. Such composite tubing frequently is superior to conventional monolithic tubing in that improved specific strength is obtained and in that the layered construction will retard failure crack propagation and thereby tend to prevent catastrophic failure. By selectively varying the lengthwise orientation of the high strength strips within adjacent layers, a pseudoisotropic material is obtained typically having a bulk strength greater than that of conventional monolithic materials. However, since the transverse strength of the strips is typically significantly less than their longitudinal strength, the composite material has a bulk strength significantly less than that of the maximum tensile strength of the elemental strips.
In contrast, the present invention utilizes, in a selected manner, glassy alloy strips to build up a thin-walled shell such that the composite wall material has a bulk strength approaching the ultimate strength of the glassy alloy strips.